Idling Problem??

[Dane]

Hey guys, got a DA9 with b18a (stock motor) in it and when idling revs climb to bout 2-2500rpm then drop back to 700ish then climb again. It keeps doing this constantly and is very annoying.
Does any1 have ideas as to how I fix this problem??

[02gzm]

tried resetting ur ecu?

[AsH_]

searh for iacv in the diy section...

and throttlebody....

[VTec1987]

Clean out the iacv and throttle body.
After you clean it and still idles, change the iacv.

[pengpeng]

check your O2 sensor wires and plug

[dc2r_fAn]

You might want to check to make sure your alternator is not starting to go bad. Your alternator is what provides electric power to your car, your car's computer, and recharges your battery when the engine is running. The more gas you press in, the faster the alternator belt spins and forces your alternator to generate more power.

Use a multimeter to make sure the voltage across your battery terminals are between 13.5 volts and 15.1 volts while pressing your accelerator 'til your reach 2500 rpm. If it is below 13.5 volts, then your alternator (needs to be replaced) is no longer producing enough power to charge your battery and sufficiently run the electrical components of your car. This could also affect your car's computer and cause your car to stall.

Good luck!

[dc2r_fAn]

also

Make sure the coolant level is full. If you unplug the idle air control valve on the back side of the intake, see what it idles at. It should either die or idle very slow (400-500 rpms) You can also check for a vacuum leak by placing your hand over the throttle body. If you can kill the engine, then there are no vacuum leaks. If the coolant is full, probably need to replace the idle air control valve

[Dane]

Thanks guys, I'll have a go at the above!

I don't think the alternator is a prob as when I first started the car the battery was low (it haden't been used in ages) after the first drive battery was perfect.

The 02 sensor's wire is a bit dodgy, how do I check to see if it is working corectly?? :cool:

[dc2dc2dc2]

hey mate had exact same problem.
cleaned IACV and TB
didn't help at all.
ended up being the thermostat.
once i changed that
all good
good luck man
:)

[EuroDude]

Had the same problem, cleaned the throttle body and that fixed it

[kayot1k]

Clean out the iacv and throttle body.
After you clean it and still idles, change the iacv.

how about diagnosing if the IACV is the problem to start with ? or whether it is indeed faulty.

bad advice my friend :thumbdwn:

[Dane]

how about diagnosing if the IACV is the problem to start with ? or whether it is indeed faulty.

bad advice my friend :thumbdwn:

I pulled the plug out of the IACV last night and it now idles better (not perfect) I also noticed that it was holding revs between gear changes and now the IACV is disconected it doesn't hold the revs any more.
So it seems the IACV is the culprut, I cleaned it uot and it did nothing. Is there any way of making sure it is faulty before I fork out a lump of cash to replace it??

BTW I have also changed the Thermostat, cleaned the throttle body, cleaned the IACV and cleaned the valve thing under the throttle body and still having dramas.

[EuroDude]

When you cleaned the throttle body, did you also clean the Idle Air Bypass valve/passage?

Before the butterfly, there is a tube/passage that lets the engine breath when the butterfly is closed during idle. If that is blocked, the ECU will compensate and constantly increase the revs to avoid stalling. On some cars, there is a small pipe that branches off the main air intake pipe and goes into the side of the engine. Remove the pipe and spray Carby/Throttle body cleaner in it. You can do it while the engine is idling if you dont want the engine to hard start when to turn it on.

[barefootbonzai]

if you have done all the above and it hasn't helped. you probably have a vacuum leak somewhere.

[Dane]

Could a dodgy pcv valve cause this??

[Dane]

Replaced the PCV last night, car now runs perfectly! No more Idle surging. WOOHOO!!!!